1. Field of the Invention
The invention relates generally to the field of storage area networks, and more particularly to providing access to a storage area network as network attached storage.
2. Background Art
Network attached storage (NAS) is a term used to refer to storage elements or devices that connect to a network and provide file access services to computer systems. NAS devices attach directly to networks, such as local area networks, using traditional protocols such as Ethernet and TCP/IP, and serve files to any host or client connected to the network. A NAS device typically consists of an engine, which implements the file access services, and one or more storage devices, on which data is stored. A computer host system that accesses NAS devices uses a file system device driver to access the stored data. The file system device driver typically uses file access protocols such as Network File System (NFS) or Common Internet File System (CIFS). NAS devices interpret these commands and perform the internal file and device input/output (I/O) operations necessary to execute them.
Because NAS devices independently attach to the network, the management of these devices generally occurs on a device-by-device basis. For instance, each NAS device must be individually configured to attach to the network. Furthermore, the copying of a NAS device for purposes of creating a back-up must be configured individually.
Storage area networks (SANs) are dedicated networks that connect one or more hosts or servers to storage devices and subsystems. SANs may utilize a storage appliance to provide for management of the SAN. For instance, a storage appliance may be used to create and manage back-up copies of the data stored in the storage devices of the SAN by creating point-in-time copies of the data, or by actively mirroring the data. It would be desirable to provide these and other SAN-type storage management functions for storage devices attached to a network, such as a local area network.
The present invention is directed to a system and method for interfacing a storage area network (SAN) with a first data communication network. One or more hosts coupled to the first data communication network can access data stored in one or more of a plurality of storage devices in the SAN. The one or more hosts access one or more of the plurality of storage devices as network attached storage (NAS). A SAN server is coupled to a SAN. A NAS server is coupled to the SAN server through a second data communication network. The NAS server is coupled to the first data communication network. A portion of at least one of the plurality of storage devices is allocated from the SAN server to the NAS server. The allocated portion is configured as NAS storage in the NAS server. The configured portion is exported from the NAS server to be accessible to the one or more hosts coupled to the first data communication network.
In a further aspect of the present invention, a system and method for managing the allocation of storage from a storage area network (SAN) as network attached storage (NAS) to a data communication network, is described. A storage management directive is received from a graphical user interface. A message corresponding to the received storage management directive is sent to a NAS server. A response corresponding to the sent message is received from the NAS server.
In still a further aspect of the present invention, an apparatus for accessing a plurality of storage devices in a storage area network (SAN) as network attached storage (NAS) in a data communication network is described. A SAN server includes a first interface and a second interface. The first interface is configured to be coupled to the SAN. The second interface is coupled to a first data communication network. A NAS server includes a third interface and a fourth interface. The third interface is configured to be coupled to a second data communication network. The fourth interface is coupled to the first data communication network. The SAN server allocates a first portion of the plurality of storage devices in the SAN to be accessible through the second interface to at least one first host coupled to the first data communication network. The SAN server allocates a second portion of the plurality of storage devices in the SAN to the NAS server. The NAS server configures access to the second portion of the plurality of storage devices to at least one second host coupled to the second data communication network.
In still a further aspect of the present invention, a storage appliance for accessing a plurality of storage devices in a storage area network (SAN) as network attached storage (NAS) in a data communication network is described.
A first SAN server is configured to be coupled to the plurality of storage devices in the SAN via a first data communication network. The first SAN server is configured to be coupled to a second data communication network. A second SAN server is configured to be coupled to the plurality of storage devices in the SAN via a third data communication network. The second SAN server is configured to be coupled to a fourth data communication network. A first NAS server is configured to be coupled to a fifth data communication network. The first NAS server is coupled to the second and the fourth data communication networks. A second NAS server is configured to be coupled to the fifth data communication network. The second NAS server is coupled to the second and the fourth data communication networks. The first SAN server allocates a first portion of the plurality of storage devices in the SAN to be accessible to at least one first host coupled to the second data communication network. The first SAN server allocates a second portion of the plurality of storage devices in the SAN to the first NAS server. The first NAS server configures access to the second portion of the plurality of storage devices to at least one second host coupled to the fifth data communication network. The second NAS server assumes the configuring of access to the second portion of the plurality of storage devices by the first NAS server during failure of the first NAS server. The second SAN server assumes allocation of the second portion of the plurality of storage devices by the first SAN server during failure of the first SAN server.
The present invention provides many advantages. These include:
1. Ease of use. A graphical user interface (GUI) of the present invention provides a convenient administrative interface. A system administrator may allocate a NAS file system with a single press of a mouse button.
2. Seamless integration into an existing SAN appliance administrative interface. The NAS functionality may be added as a new window in an existing administrative GUI, for example.
3. Maintaining the benefits of a single appliance. In a preferred embodiment, a single appliance is presented that contains data management function and NAS capabilities.
4. Full use of existing SAN appliance data management functions. The features of a SAN appliance (such as data mirroring, virtualization of storage, and instant snapshot copying of storage) are made available to NAS file systems.
5. High-availability. With multiple NAS server capability, the implementation is resistant to single points of failure.
6. High capacity. The NAS implementation is capable of providing data to a large number of clients. It is capable of providing data to UNIX and Windows hosts.
7. Minimal impact on an existing SAN appliance architecture. The NAS implementation has a minimal impact on any existing SAN appliance software code. Addition of the NAS servers does not appreciably degrade the performance of existing features of the SAN appliance.
Further aspects of the present invention, and further features and benefits thereof, are described below. The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.